Aborto espontáneo y sangrado en las primeras etapas del embarazo
Revisado por pares por Dr Philippa Vincent, MRCGPÚltima actualización por Dr Rosalyn Adleman, MRCGPÚltima actualización 15 Sept 2024
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En esta serie:Aborto espontáneo recurrente
Many women experience some bleeding in early pregnancy. About 1 in 5 recognised pregnancies end in miscarriage. Most are caused by a one-off fault in the genes. Seek medical advice if you have vaginal bleeding when you are pregnant.
Call an ambulance if the bleeding is very heavy or if you have severe tummy (abdominal) pain. Bleeding with pain can also be a sign of an ectopic pregnancy. This is less common than miscarriage but is serious and needs urgent medical care.
Losing a pregnancy can be hard for both partners. However, most couples who experience this will go on to have a successful pregnancy next time.
De un vistazo
Miscarriage is the loss of a pregnancy before the end of the 24th week.
Vaginal bleeding and lower tummy cramps are common miscarriage symptoms.
Many early miscarriages are thought to be caused by a one-off chromosome problem.
Risk factors include the mother's age, smoking, and high alcohol intake.
You should report any bleeding in pregnancy to a doctor.
En este artículo:
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What causes bleeding in early pregnancy?
About 25 out of 100 pregnant women have a small amount of bleeding (spotting) at the time of their missed period. This is sometimes called an 'implantation bleed', because it happens when the fertilised egg implants itself in the wall of the womb (uterus). It is harmless.
The most common cause of bleeding after the time of the missed period is a miscarriage. A less common cause of bleeding in pregnancy is an embarazo ectópico
What is miscarriage?
Volver al contenidoMiscarriage is the loss of a pregnancy at any time up to the end of the 24th week of the pregnancy. A loss after this time is called a stillbirth.
More than 8 out of 10 miscarriages occur before 13 weeks of pregnancy. These are called early miscarriages. A late miscarriage is one that happens from 13 weeks to 24 weeks of pregnancy.
What is a threatened miscarriage?
It is common to have some light vaginal bleeding at some point in the first 12 weeks of pregnancy. This does not always mean a miscarriage will happen. Often the bleeding settles and the developing infant is healthy. This is called a threatened miscarriage. It is unusual to have pain with a threatened miscarriage. If the pregnancy continues, there is no harm done to the baby.
In some cases, a threatened miscarriage progresses to a miscarriage.
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How common is miscarriage?
Volver al contenidoAbout one in five recognised pregnancies end in miscarriage. It is thought that about half of all pregnancies end in miscarriage but that half of these are so early that women may be unaware that they are pregnant.
The vast majority of women who miscarry go on to have a successful pregnancy next time.
Recurrent miscarriages (three or more miscarriages in a row) occur in about 1 in 100 women.
Miscarriage symptoms
Volver al contenidoThe usual symptoms of miscarriage are:
Vaginal bleeding.
Lower tummy (abdominal) cramps.
The time it takes for the bleeding to settle varies. It is usually a few days but can last two weeks or more. For most women, the bleeding is heavy with clots but not severe - it is more like a heavy period. However, the bleeding can be extremely heavy in some cases.
Missed miscarriage (no symptoms)
In some cases of miscarriage, there are no symptoms. The baby stops developing and dies but remains in the womb. There is no pain or bleeding. Some women will stop experiencing pregnancy symptoms (for example, morning sickness or breast tenderness).
This type of miscarriage may not be found until a routine ultrasonido. This may be referred to by doctors as a missed miscarriage.
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What causes miscarriage?
Volver al contenidoIt is thought that most early miscarriages are caused by a one-off problem with the chromosomes of the developing baby (fetus) in the womb. Chromosomes are the structures that contain the genetic information inherited from the parents.
If a baby (fetus) doesn't have the correct chromosomes, it can't develop properly and so the pregnancy will end. This is usually a one-off event and rarely occurs again. Such genetic errors become more common as the mother gets older.
Miscarriage is not caused by lifting, straining, working too hard, estreñimiento, straining at the toilet, sex, eating spicy foods or taking normal exercise.
There is no evidence that waiting for a certain length of time after a miscarriage improves the chances of having a healthy pregnancy next time.
Investigations into the cause of a miscarriage are not usually carried out until after three or more miscarriages in a row. This is because most women who miscarry will not miscarry again.
Two miscarriages are more likely to be due to chance than to some underlying cause. Even after three miscarriages in a row, six women out of every ten will have a successful pregnancy next time around.
Risk factors for miscarriage
Volver al contenidoThe risk of miscarriage increases with the mother's age. In women aged 20-24 approximately 9 in 100 pregnancies end in miscarriage. In women aged over 45 the risk increases to 75 in 100.
The risk of miscarriage also increases with increasing age of the father. If the father is aged over 45 there is an increased risk of miscarriage. The effect of the father's age is not as marked as that of the mother's age.
Women are also at a greater risk of having a miscarriage if they:
Smoke. The risk increases the more cigarettes you smoke.
Drink too much alcohol. Drinking four units of alcohol a week (one unit is half a pint of beer or a small glass of wine) has been shown to increase the risk of miscarriage.
Have had fertility problems or it has taken a long time to conceive.
Have any abnormalities of the womb (uterus) or a weakness of the neck of the womb (the cervix).
Have certain medical conditions (for example, lupus eritematoso sistémico, síndrome antifosfolípido. polycystic ovary syndrome, thyroid disease).
Tener diabetes mellitus que no está bien controlado.
Have particular infections like listeria y Sarampión alemán (rubella).
Are underweight (BMI less than 19) or overweight (BMI over 25).
Treatment for miscarriage
Volver al contenidoOnce the cause of bleeding is known, treatment options will be discussed.
Natural or expectant management
Many women now opt to 'let nature take its course'. This is called expectant management. In most cases the remains of the pregnancy are passed out through the vagina and the bleeding stops within a few days of this, although can take up to 14 days to settle.
However, if the bleeding worsens and becomes heavier or does not settle then alternative treatment may be offered. Expectant management may not be advised if there has been a previous miscarriage or if there is a bleeding disorder or any evidence of infection.
Some women prefer to have a definitive treatment rather than taking this approach.
Medicina
In some cases medical treatment for a miscarriage is suggested. This is a tablet taken either by mouth or inserted into the vagina. This medicine helps to empty the womb (uterus) and can have the same effect as an operation.
Some women experience quite severe tummy (abdominal) cramps with this treatment. It is possible to continue to bleed for up to three weeks when medical treatment is used. However, the bleeding should not be too heavy. Many women prefer this treatment because it usually means that they do not need to be admitted to hospital and do not need an operation.
An operation may be offered if the bleeding does not stop within a few days, or if the bleeding is severe.
Cirugía
If the options above are not suitable or are not successful then an operation is likely to be offered. The operation most commonly performed to remove the remains of the pregnancy is called surgical management of miscarriage (SMM). It is also sometimes called evacuation of retained products of conception (ERPC).
In this operation, the neck of the womb (the cervix) is gently opened and a narrow suction tube is placed into the womb to remove the remains of the pregnancy. This operation takes around 10 minutes.
This may be performed without the need for a general anaesthetic in some cases. This is called a manual vacuum aspiration (MVA).
There is a small risk of developing an infection after having this operation. This happens in about 2 cases out of 100. Prompt medical advice should be sought if there is a temperatura alta (fiebre), any offensive-smelling vaginal discharge or abdominal pains after a SMM. Any infection is usually treated successfully with antibióticos.
Do I need to go to hospital?
Volver al contenidoAny bleeding in pregnancy should be reported. It is important to get the correct diagnosis, as miscarriage is not the only cause of vaginal bleeding.
Most women with bleeding in early pregnancy are seen by a doctor who specialises in pregnancy - an obstetrician. This is often in an Early Pregnancy Assessment Unit at the local hospital.
Some early pregnancy units allow women to self-refer into them; others require a GP referral or referral from a doctor in the emergency department. It is usual to have an ultrasound scan. This is usually done by inserting a small probe inside your vagina. This helps to determine whether the bleeding is due to:
A threatened miscarriage (a heartbeat will be seen inside the womb (uterus)).
A miscarriage (no heartbeat is seen).
Some other cause of bleeding (such as an ectopic pregnancy - see above).
Sometimes blood tests to look for the pregnancy hormone (beta-HCG) are used. If it is unclear from the ultrasound scan or blood tests whether the pregnancy is healthy or not then a repeat scan in one to two weeks is often suggested.
Women who have already had a scan confirming the baby's heartbeat and who have never had a miscarriage before may be advised that they do not need another scan. However, the early pregnancy unit will advise further on this.
Women who have had a scan confirming the presence of a heartbeat and who have had a previous miscarriage should be offered vaginal progesterone pessaries to be used until the end of the 16th week of pregnancy. This will be arranged in the early pregnancy unit.
Mental health impact of miscarriage
Volver al contenidoMany women and their partners find that miscarriage is distressing. You may have feelings of:
Choque.
Duelo
Guilt.
Loss.
Anger.
These feelings are common. It is best not to bottle up feelings but to discuss them as fully as possible with partner, friends, a healthcare professional or anyone else who can listen and understand.
As time goes on, the sense of loss usually becomes less. However, the time this takes varies greatly. Pangs of grief sometimes recur out of the blue. The time when the baby was due to be born may be particularly sad. The Miscarriage Association (see below for details) can offer support.
Selecciones del paciente para Sangrado en el embarazo

Embarazo
Aborto espontáneo recurrente
La pérdida de un embarazo muy deseado puede ser devastadora, y aún más si ocurre nuevamente. Este folleto explica la definición de aborto espontáneo recurrente y explora las pruebas y tratamientos que pueden ser necesarios. La buena noticia es que el pronóstico final es generalmente bueno, ya que la mayoría de las parejas que han experimentado abortos espontáneos recurrentes logran tener un embarazo exitoso.
por la Dra. Mary Harding, MRCGP

Embarazo
Embarazo molar
Un embarazo molar (mola hidatiforme) ocurre cuando una masa de tejido crece dentro de tu útero que no se desarrollará en un bebé. Es el resultado de una concepción anormal. Puede causar sangrado o vómitos severos en las primeras etapas del embarazo y generalmente se detecta en una ecografía temprana del embarazo. Necesita ser removido y la mayoría de las mujeres pueden esperar una recuperación completa.
por el Dr. Doug McKechnie, MRCGP
Preguntas frecuentes
What is an 'implantation bleed' during early pregnancy?
An implantation bleed is a small amount of spotting that can occur around the time of a missed period. It happens when the fertilised egg attaches itself to the wall of the womb (uterus). This type of bleeding is considered harmless.
If I experience light bleeding in the first 12 weeks, does it automatically mean I'm having a miscarriage?
Not necessarily. Light vaginal bleeding in the first 12 weeks of pregnancy is common and does not always lead to a miscarriage. Often, the bleeding stops, and the pregnancy continues healthily. This situation is referred to as a 'threatened miscarriage'.
How long does it take for bleeding to stop after a miscarriage?
The duration of bleeding after a miscarriage can vary. It usually lasts a few days but might continue for two weeks or even longer. For most women, the bleeding will be heavy with clots, similar to a heavy period, but not typically severe.
Can everyday activities like lifting or exercising cause a miscarriage?
No, common activities such as lifting, straining, working hard, constipation, straining at the toilet, sex, eating spicy foods, or regular exercise do not cause miscarriage. Most early miscarriages are due to a one-off problem with the baby's chromosomes.
After a miscarriage, do I need to wait a certain amount of time before trying to get pregnant again?
There is no evidence to suggest that waiting a specific length of time after a miscarriage improves the chances of having a healthy pregnancy next time. The vast majority of women who experience a miscarriage go on to have a successful pregnancy in the future.
What are the options for managing a miscarriage if I don't want surgery?
There are a few options besides surgery. One is 'expectant management', where you allow the pregnancy remains to pass naturally. Another option is medical treatment, which involves taking a tablet by mouth or vaginally to help empty the womb. This usually means you don't need to be admitted to hospital for an operation, but you may experience cramps and bleeding for up to three weeks.
If I've had a previous miscarriage and now have a confirmed heartbeat, is there anything that can be done to help prevent another miscarriage?
Yes, if you have had a previous miscarriage and a scan confirms a heartbeat, you should be offered vaginal progesterone pessaries. These are typically used until the end of the 16th week of pregnancy and will be arranged at an early pregnancy unit.
Lecturas adicionales y referencias
- Nanda K, Lopez LM, Grimes DA, et al; Expectant care versus surgical treatment for miscarriage. Cochrane Database Syst Rev. 2012 Mar 14;3:CD003518. doi: 10.1002/14651858.CD003518.pub3.
- Embarazo ectópico y aborto espontáneo: diagnóstico y manejo inicial; Guía NICE (última actualización agosto 2023)
- ; Bleeding in Early Pregnancy. Am Fam Physician. 2019 Feb 1;99(3):Online.
- Sapra KJ, Joseph KS, Galea S, et al; Signs and Symptoms of Early Pregnancy Loss. Reprod Sci. 2017 Apr;24(4):502-513. doi: 10.1177/1933719116654994. Epub 2016 Sep 27.
- Aborto espontáneo; NICE CKS, octubre 2023 (solo acceso en el Reino Unido)
- La Asociación de Aborto Espontáneo
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Sobre el autorVer biografía completa

Dr Rosalyn Adleman, MRCGP
MRCGP
La Dra. Rosalyn Adleman es una médica de cabecera del NHS que trabaja en el norte de Londres.
Acerca del revisorVer biografía completa

Dra. Philippa Vincent, MRCGP
Médico General, Autor Médico
MB BS, Bsc, MRCGP (2000), DCH, DFSRH, DRCOG
Dra Philippa Vincent es un médico de cabecera del NHS que trabaja en el norte de Londres.
Historial del artículo
La información en esta página está escrita y revisada por pares por clínicos calificados.
Próxima revisión: 14 de septiembre de 2027
15 Sept 2024 | Última versión

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